Contour Enthusiasts Group Archives Forums Modifications General Mods Rifle the intake?

Would doing this help any? I'm slowly learning the air in to the engine has to come in and go out with as little turbulance as posible, so would rifleing the intake make the air cind of turbine in to the engine? I could be way off base. Just ignor this if I'm a dumba$$. :rolleyes:

Every idea has some merrit, but I think that you will get a lot of interesting responses from not so polite people. I will take a stab at giving a few reasons why I think it wouldn't work. You can compare what I say to other people and then decide what part of it is knowledge to take away with you.
In general, 'rifling' implies spiral grooves through the manifold passages. There are so many factors based on size and spacing, but I think they would only create more drag as they provide more surface area in the same pipe. The closest thing I can think of to what you are talking about is General Motors' Vortech V6 manifolds. They use a proprietary manifold to increase the velocity of the air going into the cylinders that involves a circular path of travel. I would go and research that if I were you and learn what they did.
Some other people may have some other ideas, but in general, the straighter the path for the air to travel, the less it loses its velocity and the less drag.

warmonger

Correct, warmonger, about the drag induced by the rifling ridges.

We are discussing air flow vs. mechanical flow of a bullet. The same theories do not apply.

The ideal air flow passage will be as straight & smooth as possible with no restrictions or protuberances into the air stream. Depending on the designer's intent, of course, the passage could be different than the ideal in regards to surface finish, obstructions, diameter, cross-sectional shape, etc. in order to achieve certain flow parameters.

But generally the rifling idea in regards to air flow is not valid for inducing swirl.
In fact some OEM & aftermarket cylinder heads have combustion chambers designed to induce swirl, but it is induced by the shape of the chamber, not the surface finish.

The other thing to keep in mind is that all the air is not moving at the the same speed. If you plot gas velocity against port location, it's traveling fastest in the center and slowest by the port wall. At the point that the gas is in contact with the port wall is the boundary layer, and the gas flow is close to 0. This is the where the firling would be, so it would have almost no effect on the direction of air flow.
Now, one of the reasons for not putting a mirror finish on the port wall is it makes the boundary layer thicker (than having a slightly textured surface which breaks up the boundary layer) which causes more drag.

Isn't that the same idea as the "TornadoSaver" thing that adds 25HP? :rolleyes:

I thought the swirling would serve no point in atomization and intake of fuel.

Engines induce 'swirl' for cylinder filling, scavange and correct mixing by the '3 Zone' System of intake valve Vs port position.As most multi valve engines have an 'open' chamber design the benifits of 'squish' etc are non-existent.Anything done to the air flow prior to the '3 Zones' make little difference to the power or IMEP of the motor....

Don't some also induce swirl so as to prevent hotspots and the denotation that can result?

Wow I feel like a moron.

You guys know WAY to much.

Time Young Grasshopper! Time!
As long as you look and listen to people all your life you will learn a lot. I don't care what age a person is I listen to what they have to say... for a while anyway
I also read a lot. I also learn from every problem that I have to face and overcome. Some people have a learning curve that hits an asymptote when they hit their 30's; I don't understand that and I pity them. Don't be like that.

That is one of the reasons I like to read posts on here, I learn something every day.

Warmonger (take it for what its worth)

Wouldn't it be better to rife the exhaust so that you're creating a tornado effect to pull the spent gasses out of the chamber ?

Just an idea, not sure that it's correct.

jim